/**
 * author: MaHX
 * date: 2019/8/19/0:53
 * description:
 **/
public class Fbnqsl {
    public static void main(String[] args) throws Exception {
        System.out.println(run(50));
    }
    public static long run(int n){
        if (n == 1 || n == 2){
            return 1;
        }else {
            return run(n-1)+run(n-2);
        }
    }
}
